First stab at building a PDF for printable claim labels

badger/printing.py

@@ -0,0 +1,143 @@
+#!/usr/bin/env python
+"""Quick and dirty render-to-PDF for badge award claim codes"""
+
+import logging
+import urllib
+import urllib2
+try:
+    from cStringIO import cStringIO as StringIO
+except ImportError:
+    from StringIO import StringIO
+
+from reportlab.pdfgen import canvas
+from reportlab.lib import pagesizes
+from reportlab.lib.units import inch
+from reportlab.platypus import (
+    SimpleDocTemplate, BaseDocTemplate, Paragraph, Spacer, PageBreak, 
+    Frame, FrameBreak, PageTemplate, Image, Table)
+from reportlab.lib.styles import getSampleStyleSheet, ParagraphStyle
+from reportlab.rl_config import defaultPageSize 
+from reportlab.lib.units import inch 
+from reportlab.lib.enums import TA_LEFT, TA_CENTER
+from reportlab.lib import colors
+
+from django.http import (HttpResponseRedirect, HttpResponse,
+        HttpResponseForbidden, HttpResponseNotFound)
+
+from django.utils.html import conditional_escape
+
+
+# Constants hard-coded to print onto Avery 5630 or Avery 5260 labels
+# TODO: Make formats / templates switchable
+top_margin = (0.5 * inch)
+left_margin = (0.1875 * inch)
+width = 2.52 * inch
+height = 1.0 * inch
+vertical_spacing = 0 * inch
+horizontal_spacing = 0.10 * inch
+columns = 3
+rows = 10
+
+
+def render_claims_to_pdf(request, slug, claim_group, deferred_awards):
+    response = HttpResponse(content_type='application/pdf; charset=utf-8')
+    response['Content-Disposition'] = ('attachment; filename="%s-%s.pdf"' %
+            (slug.encode('utf-8', 'replace'), claim_group))
+    doc = BaseDocTemplate(response, pageSize=pagesizes.letter,
+            topMargin=top_margin, leftMargin=left_margin)
+
+    debug = (request.GET.get('debug', False) is not False)
+    
+    # TODO: Turn off the boundaries, once we're done tweaking the layout to
+    # match label sheets
+    # if debug: show_boundary = 1
+    # else: show_boundary = 0
+    show_boundary = 1
+
+    # Build frames for labels in the template
+    frames = []
+    for r_idx in range(0, rows):
+        for c_idx in range(0, columns):
+            frames.append(Frame(
+                left_margin + (c_idx * (width + horizontal_spacing)),
+                doc.height - (r_idx * (height + vertical_spacing)),
+                width, height,
+                leftPadding=0, rightPadding=0,
+                bottomPadding=0, topPadding=0,
+                showBoundary=show_boundary
+            ))
+
+    # Add the template to the page.
+    template = PageTemplate(frames=frames)
+    doc.addPageTemplates(template)
+
+    # Build some common styles
+    style = ParagraphStyle(name='normal', alignment=TA_CENTER,
+        fontName='Helvetica', fontSize=9, leading=9)
+    code_style = ParagraphStyle(name='code', alignment=TA_CENTER,
+        fontName='Courier', fontSize=9.5, leading=9.5)
+
+    # Fill out the template with claim codes.
+    items = []
+    for da in deferred_awards:
+        badge = da.badge
+        award_url = request.build_absolute_uri(da.get_claim_url())
+
+        badge_img = StringIO(badge.image.file.read())
+
+        # TODO: Stop abusing the Google Charts API and get our own QR code
+        # baking on premises.
+        try:
+            qr_url = ("http://chart.apis.google.com/chart?%s" %
+                urllib.urlencode({'chs':'%sx%s' % (250, 250), 
+                                  'cht':'qr', 'chl':award_url, 'choe':'UTF-8'}))
+            qr_img = StringIO(urllib2.urlopen(qr_url).read())
+        except Exception, e:
+            return HttpResponse('QR code generation failed: %s' % e,
+                                status=500)
+
+        # Build the badge label out as a table...
+        table_data = (
+            (
+                Image(badge_img, 0.6 * inch, 0.6 * inch),
+                Image(qr_img, 0.6 * inch, 0.6 * inch)
+            ),
+            (
+                # Use resize_para to shrink the font size as title gets longer.
+                resize_para(badge.title),
+                (
+                    resize_para(request.build_absolute_uri('/'),
+                                max_width=0.85 * inch),
+                    Paragraph(da.claim_code.upper(), code_style),
+                )
+            ),
+        )
+
+        table_style = (
+            ('ALIGN', (0,0), (-1,-1), 'CENTER'),  
+        )
+
+        if debug:
+            table_style = table_style + (
+                ('GRID', (0,0), (-1,-1), 1, colors.black),  
+            )
+
+        items.append(Table(table_data, style=table_style))
+        items.append(FrameBreak())
+
+    doc.build(items)
+
+    return response
+
+
+def resize_para(str, max_size=11.0, min_size=2.0, max_width=(0.3125*inch),
+                font_name='Helvetica', alignment=TA_CENTER):
+    size = max_size
+    while size > min_size:
+        para = Paragraph(str, ParagraphStyle(name='Size %s' % size,
+            alignment=alignment, fontName=font_name, fontSize=size,
+            leading=size+0.25))
+        if para.minWidth() <= max_width:
+            break
+        size -= 0.125
+    return para

badger/urls.py

@@ -22,6 +22,9 @@ urlpatterns = patterns('badger.views',
         name='badger.award_detail'),
     url(r'^badge/(?P<slug>[^/]+)/claims/?$', 'manage_claims',
         name='badger.manage_claims'),
+    url(r'^badge/(?P<slug>[^/]+)/claims/(?P<claim_group>.+)\.pdf$', 'claims_list',
+        kwargs=dict(format='pdf'),
+        name='badger.claims_list_pdf'),
     url(r'^badge/(?P<slug>[^/]+)/claims/(?P<claim_group>[^/]+)/?$', 'claims_list',
         name='badger.claims_list'),
     url(r'^claim/(?P<claim_code>[^/]+)/?$', 'claim_deferred_award',

badger/views.py

@@ -216,13 +216,18 @@ def claim_deferred_award(request, claim_code=None):
 
 @require_http_methods(['GET', 'POST'])
 @login_required
-def claims_list(request, slug, claim_group):
+def claims_list(request, slug, claim_group, format="html"):
     badge = get_object_or_404(Badge, slug=slug)
     if not badge.allows_manage_deferred_awards_by(request.user):
         return HttpResponseForbidden()
 
     deferred_awards = badge.get_claim_group(claim_group) 
 
+    if format == "pdf":
+        from badger.printing import render_claims_to_pdf
+        return render_claims_to_pdf(request, slug, claim_group,
+                                    deferred_awards)
+
     return render_to_response('badger/claims_list.html', dict(
         badge=badge, claim_group=claim_group,
         deferred_awards=deferred_awards